Mechanically, how high can I go?

[Bobby]

I've been thinking lately how high the p3a can go. And yes I know it can't go over 1600 ft because of the geofence, that was a bit sadening to find out.

However, I wonder, if say that limit wasn't existant, or was defeated, and let's just say hypothetically for some reason I'm in the middle of the ocean and planes don't exist so there is no danger, how high can a p3a go?

I figure two things mess that up, wind and a dismal ascention descention rate. Seriously I think the fc40 went faster down, but maybe that's some tipping issue countermeasure. Other than that, how would the wind affect it at 8000-10000 feet? I'm no pilot, so I have no idea.

So, without 3rd party safety concerns, how high?

 

[N017RW]

I've been thinking lately how high the p3a can go. And yes I know it can't go over 1600 ft because of the geofence, that was a bit sadening to find out.

However, I wonder, if say that limit wasn't existant, or was defeated, and let's just say hypothetically for some reason I'm in the middle of the ocean and planes don't exist so there is no danger, how high can a p3a go?

I figure two things mess that up, wind and a dismal ascention descention rate. Seriously I think the fc40 went faster down, but maybe that's some tipping issue countermeasure. Other than that, how would the wind affect it at 8000-10000 feet? I'm no pilot, so I have no idea.

So, without 3rd party safety concerns, how high?

They are spec-ed to 6000 meters. Likely due to air density requirements.
There is at least one vid of a P2 at Everest base camp (~17k ft.) from 2-3 years ago.

 

[Sasquad]

400 feet, it's a law! Abide by the rules of the land, so we may all enjoy this hobby.

 

[redbusdriver]

All aircraft have a service ceiling, the point where lift and thrust give out and are equaled by drag and gravity. In the case of a quad copter this is the point where lower air density makes the thrust from the blades unable to carry the weight of the quad.

DJI says 6000 meters, or roughly 20,000 ft above sea level. There are places in the world where you can be at or above 20K ft MSL and still be less than 400 ft above the ground, but not in the USA unless you are on Denali which is in a national park anyway.

Using rough numbers, at 18,000 ft MSL (above sea level) the atmosphere is half as dense as it is at sea level, and quite a bit colder as well, 2 degrees C or 3 degrees F colder per 1000 ft of altitude. There is an atmospheric model called the ISA, international standard atmosphere, which is used to calculate and measure aircraft performance (and other things).

I was cruising at FL370 (37,000 ft MSL on 29.92"/1013 MB altimeter setting) last week and saw -66C on the OAT, a full 10 C lower than ISA. No, I was not piloting my P3P! That was some chilly air.

As an aside, when I first got my P3P I had the impression that 400' AGL was quite low as my frame of reference flying large airplanes was in play. After seeing my drone at 400' AGL I realize it is plenty high enough. It's all relative to the size of aircraft and mission. Have fun and fly safe!

 

[Mr. Salty]

400 feet, it's a law! Abide by the rules of the land, so we may all enjoy this hobby.

Not in the middle of the ocean it isn't.

 

[aermale]

19,800 ft. It's on a YouTube video somewhere.

 

[Pharm]

19,800 ft. It's on a YouTube video somewhere.

No YouTube videos necessary. Go to the DJI website and look at the specs for the P3A.

 

[Loz]

400 feet, it's a law! Abide by the rules of the land, so we may all enjoy this hobby.

Which land is that? - that was a reasonable polite open question, not statement of intent, on a global forum, your reply missed the point on so many levels.

 

[Sasquad]

Which land is that? - that was a reasonable polite open question, not statement of intent, on a global forum, your reply missed the point on so many levels.

USA. 400 feet, why care how much further, or higher out will go if there is not intent?

 

[Richard R]

USA. 400 feet, why care how much further, or higher out will go if there is not intent?

In the US, 400 ft agl is only the law for Part 107 flights. For hobby flying, it is the recommended maximum height. And, redbusdriver, really well done explanation on air density and service ceiling. Might add that even at lower altitudes, reduced density can have an impact. The bird has to work harder and could cause a miscalculation on having enough battery to return home.

 

[With The Birds]

USA. 400 feet, why care how much further, or higher out will go if there is not intent?

The OP is asking a hypothetical question. I would think that is natural in any pursuit where someone has an interest. People often attempt to calculate what ET a modified vehicle may achieve over the quarter mile and never put the car in the strip, let alone a public roadway.

 

[Richard R]

The OP is asking a hypothetical question. I would think that is natural in any pursuit where someone has an interest. People often attempt to calculate what ET a modified vehicle may achieve over the quarter mile and never put the car in the strip, let alone a public roadway.

And the OP set that tone with the title of his post 'mechanically....' It's not a problem for me in the Midwest of the US, but there are pilots on this forum who do have to contend with the effects of reduced density altitudes and for whom the local ground altitude can start becoming an issue. Thankfully, the OP did get the answer to his question and some good technical input and advice.

 

[Richard R]

I've been thinking lately how high the p3a can go. And yes I know it can't go over 1600 ft because of the geofence, that was a bit sadening to find out.

However, I wonder, if say that limit wasn't existant, or was defeated, and let's just say hypothetically for some reason I'm in the middle of the ocean and planes don't exist so there is no danger, how high can a p3a go?

I figure two things mess that up, wind and a dismal ascention descention rate. Seriously I think the fc40 went faster down, but maybe that's some tipping issue countermeasure. Other than that, how would the wind affect it at 8000-10000 feet? I'm no pilot, so I have no idea.

So, without 3rd party safety concerns, how high?

Don't worry about decent rate. When you run out of battery, the bird will come down plenty fast enough LOL!!

 

[Bobby]

Thanks guys, I'm glad the majority got the point. Which I thought I had made abundantly clear.

"However, I wonder, if say that limit wasn't existant, or was defeated, and let's just say hypothetically for some reason I'm in the middle of the ocean and planes don't exist so there is no danger, how high can a p3a go?"

Yes, that's the point. Planes do exist, that's why i said hypothetically, but there is always 'that guy' right? Still, I did get some very good answers to cure my curiosity. Thanks guys!

 

[redbusdriver]

In the US, 400 ft agl is only the law for Part 107 flights. For hobby flying, it is the recommended maximum height. And, redbusdriver, really well done explanation on air density and service ceiling. Might add that even at lower altitudes, reduced density can have an impact. The bird has to work harder and could cause a miscalculation on having enough battery to return home.

Thanks Richard,
In actual practice on big planes performance is affected mostly by pressure, temperature and weight, with a very slight nod to humidity. For the purpose of this discussion I tried to simplify the concepts. OP Bobby asked for the "mechanical limit", which in aircraft performance terms is the same as the "service ceiling". In the big aircraft world this is a specific number based on certification testing. For instance the plane I fly at work, the Airbus 320 series, this is 39,800 ft MSL.

An interesting result of the new electric small human carrying planes is a plane that does not lose weight as it flies, and drones are in this category as well. My work plane gets lighter by about 100 lb per minute in cruise flight. This has an obvious effect on performance as well. On a long flight from the east coast of the US to the west coast, we start out very heavy and only able to fly at 34,000', climbing to 36,000' several hours into the flight and eventually reaching 38,000' about an hour before reaching the destination.

There are other analogues to big planes as well, the IMU (or dual IMUs on the P4P) are functionally similar to AHRS (attitude heading reference systems) on larger planes, to which we add IRUs (inertial reference systems), GPS, radar altimeters, and air data reference systems. The Phantom's ground facing sonar is functionally similar to our radar altimeters, and some functions of Autoland are similar as well. The P4P introduced dual IMUs, redundancy being a concept we have had in commercial planes for many years.

In conclusion, these are incredibly sophisticated aircraft we have at our disposal, amazing technology that would have been financially unobtainable just a few years ago!

Redbusdriver

 

[OkiePhlyer]

Redbusdriver,

I'm curious...which airline do you fly for?

 

[HWCM]

400 feet, it's a law! Abide by the rules of the land, so we may all enjoy this hobby.

BAHAHAHA. Are you going to tell on him? P.S. IT IS NOT THE LAW.

 

[Meta4]

"However, I wonder, if say that limit wasn't existant, or was defeated, and let's just say hypothetically for some reason I'm in the middle of the ocean and planes don't exist so there is no danger, how high can a p3a go?"

Looking at the hypothetical scenario, if you only wanted to go high and didn't care about the return the answer is fairly simple.
If you could get about 23 mins from a battery, multiply that by 5 metres/second and you get 6900 metres
If you want to get your Phantom back and the higher level wind doesn't carry it away, you have 5 m/s climbing and 3 m/s descending which means you could allocate 37% of your battery to the climb and 63% to the descent.
Using 23 mins battery time that would get you up about 2550 metres.

 

[redbusdriver]

Redbusdriver,

I'm curious...which airline do you fly for?

My company does not allow me to identify it in public forums, so I will just say there is a hint in my username. We are also in the process of changing from red to blue. Sorry to be coy but I like my job and want to keep it.

 

[DPD]

Airbus???